Thanks for your replies,
as a matter of fact , I'd installed Linux in text mode and ran it in text either.
Export display did not help me. I tried startx as mr. Hajigholamali stated,, it worked in my case.
I found another way for what I needed. Actually I wanted to log ino text mode, but install programs like "Weblogic". I used Xmanager. that was goood also.
Anyway, thanks